no timing marks

[kozzy17]

hi i need some help im putting together a 2003 400ex and on the sprocket there is no timing marks. i have it facing the outside and im just trying to find out how to make sure it will be on right. im not real experienced in this but any help would be nice thank you

[cataway]

what are you talking about ?

[GPracer2500]

Is it an aftermarket cam chain sprocket? Are the bolt holes slotted for adjustment? All stock 400EX cam sprockets have timing marks. There should be three of them, spaced 90 degrees apart. Like this:



An aftermarket cam sprocket with slotted bolt holes (used for advancing/retarding the cam timing) and no timing marks will likely need to be degreed in with a degree wheel. You could eyeball it (risky) and/or use the cam's sprocket flange to align but using a degree wheel would be the proper way. If you did try and just use the cam's sprocket flange, they would be aligned straight up and down. You could also mark the sprocket yourself. But then the timing will only be as accurate as your marks.

If you're not using a service manual, you probably should be. You can generally get a PDF version on Ebay for cheap.

[kozzy17]

thank u very much i appreciate your help. never replaced the sprocket on it before so someone must have put a new one on it.